Existing technology for the uninterrupted screening of multiple rolls of motion picture film requires synchronization of the film with the associated digital audio by either the application of the digital audio data to the film itself or by the application of a special time code directly to the film. Examples of such systems are described in U.S. Pat. Nos. 5,485,232 and 5,450,146. These systems are used during the printing of the finished film for theatrical release. All rely on a sync relationship between picture and audio that is both pre-established and permanent. No means have been provided to quickly synchronize or alter the synchronization of random pieces of picture and sound, such as are found in the assembly and viewing of "Dailies" which are the printed pieces of footage that represent the results of one day's filming of various scenes.
Dailies are printed and viewed as soon as possible (usually within 24 hours) by the Director or other film personnel in order to be sure that no problems have occurred which would require the scene to be reshot. These scenes are typically assembled in a haphazard manner and a method of randomly accessing the audio portion of each scene, matching it to the appropriate film footage, and then quickly synchronizing sound and picture, is needed. Furthermore, it is desired that multiple rolls of these scenes be screened continuously, by switching back and forth between multiple projectors (usually two).
Presently, the synchronization of picture and sound for viewing Dailies is all done manually with splicers and adhesive tape. The Dailies are viewed by simultaneously running a reel of film and a separate reel of sound tape which have been hand synchronized.
To describe in more detail the systems and methods currently in practice, a few terms must be defined. A "Scene" is commonly understood to mean a particular portion of a film's script. Thus Scene 93 may be the Car Chase and Scene 54 may the Love Scene. A "Take" is one recorded performance of a Scene and each Scene may have many Takes.
The "Clapper" or "Sticks" refers to the brightly painted pieces of wood that are brought together with a loud bang at the beginning of each Take. The filmed image of the Sticks coming together is used in conjunction with their recorded sound or report to provide a common audio and visual reference point for synchronization.
As a film is being shot, only selected Takes are chosen by the Director to be printed. These Takes are circled on the camera reports that are sent to the film laboratory along with the original negative. The Production Sound Mixer also indicates by the "Circled Takes" on his sound report, which Takes are to be transferred from the production sound masters to perforated magnetic film.
When the negative arrives at the film laboratory it is known as a "Camera Roll". The Camera Rolls are developed and then physically cut, with all of the circled takes spliced together into "Lab Rolls". These Lab Rolls are approximately 1000 feet long. A color corrected "Work Print" is made from each Lab Roll. The Work Print is then sent to the Assistant Editor in the Editing Room.
While the negative is being processed, the production sound masters are being transferred at a separate facility. The production tapes are most commonly DAT (Digital Audio Tape), but analog 1/4" tape is still used, and occasionally other recording media as well. Most production recording is Monaural or 2-track Stereo, but can be 4, 8 or more channels. The sound for the Circled Takes is transferred monoaurally to perforated magnetic film, also known as "Stripe". Any stereo or multi-track elements are usually combined, however the production sound mixer may request that only one side of a stereo pair or selected channels of a multi-track be transferred. After the sound is transferred, the Stripe is then also sent to the Editing Room.
When the Work Print arrives at the Editing Room, the Lab Rolls are rearranged into "Dailies Rolls". This is done because the Lab assembled their Rolls without regard for sequencing. The Lab simply splices together the designated Takes until they have a Roll approximately 1000 feet long and then they start on a new Roll. One Lab Roll may contain Takes from both Scene 93 and Scene 54. The Assistant Editor wants Dailies Rolls that contain Takes from only one Scene.
A "Head Leader" is attached to each Dailies Roll. This is done to protect the Work Print and to provide a standard reference frame from which the Dailies Roll is measured and played. The S.M.P.T.E. (Society of Motion Picture & Television Engineers) Standard Head Leader is the industry standard. It measures exactly 12 feet from the specific frame marked, "Picture Start", to its end which is attached to the first frame of action (F.F.O.A.) of the Work Print.
After being leadered, the Dailies Roll is then edge coded by a machine that prints consecutive numbers on the film at 1 foot intervals. The Acmade.RTM. coding machine is the industry standard. Using a ribbon, it prints eight characters between the perforations on the side of the film. In standard practice, there is a three digit numeric prefix, an optional letter (A through E, plus M, P, W and X), and a four digit numeric suffix. Thus 000 0000, 123A4567, 054 1000, and 999X9999 are all possible combinations. The suffix number automatically increases with each foot of film that is run through the machine.
The assistant Editor codes the Dailies Rolls so that the code prefix indicates the Scene contained in that Roll. For example, the Roll containing Sc. 53 would be coded 053 1000. A Scene may fill several Dailies Rolls, so the first roll is given the suffix 1000, the second roll 2000, etc.
The coding machine is always started on the "Picture Start" frame of the standard 12 foot leader, so that the first frame of action in Roll 054 1000 would be coded 054 1012, which is 12 feet: from the "Picture Start" frame.
As the Dailies Rolls are built, the Assistant Editor enters into a log book the relevant information for each Take on the Roll. Such information includes, for each Take on the Roll, the Scene and Take number, the first and last Acmade code number, the first and last Key Code number, (a human readable number placed of the edge of the negative at the time of manufacture), the Camera Roll number, the Lab Roll number, the Sound Roll number, a description of the Take, and the date that it was shot.
The next step is to put the Sound into synchronization with the Picture. First, the Assistant winds through the Work Print and finds the Clapper Frame for each Take on the roll. This is the first frame of film that shows the Clapper Boards fully closed. For each Take, this frame is then clearly marked with a grease pencil, a large "X" being the standard mark. The Scene and Take number are also written on the film in large print adjacent to this "X". Next, the roll of Stripe (perforated magnetic film) is listened to and the exact point of the first modulation of the sound of the Clapper closing is found and marked on the Stripe with a felt pen, for each Take.
The Work Print and Stripe are then run through a "Synchronizer", a device with toothed wheels that measures the two pieces of film simultaneously and insures that exactly the same amount of each passes through. The mark on the Stripe audio track indicating the Clapper's report is brought into alignment with the mark on the picture indicating the first frame of the Clapper fully closed. This is always done by manipulating the length of the Stripe, either by removing excess film or adding silent leader.
Once the Stripe for each Take on the Roll is put into sync with the corresponding Work Print, it is checked on a film viewing machine, such as a KEM.RTM. flatbed viewing and editing machine. This must be done because occasionaly Takes are shot in which the Clapper cannot be seen or in which its report is inaudible. In such cases, no formal sync relationship exists and one can only be found by viewing the Take and searching for an alternate reliable sync reference point. These are often created by chance, such as when an actor closes a door or puts a glass down on a table. Events such as these are reliable in that they result in an audible report that may be associated with a unique frame of film. Lacking these, spoken dialogue may be used to find the correct sync relationship, with hard consonents sch as "P" or "T" being preferred because of the obvious lip movements associated with them. This last method is known as "Lip Synching" and is often quite subjective.
After they are synchronized and checked, the Dailies Rolls and Stripe are taken to a screening room and projected by a system capable of interlocking the two pieces of film. As stated before, it is desired that the Dailies be shown without interruption between Rolls. Therefore, two motion picture projectors and two magnetic tape players are required.
After a screening of these Dailies by the Director, and/or other personnel, the separate Rolls of picture and sound are sent to a Telecine facility and transferred to videotape. Usually the final editing of the film is done on a computer and the Stripe audio track is never used again.